Breaker block for rolling mills



oct. 7, 1952 W, H BAILEY 2,612,798

v BREAKER BLOCK FOR ROLLING MILLS Filed oct. 28, 1949 Inventor:

' d Attorneys.

Patented Oct. '7, 1.952

to The British Iron. an

London, England; assi'gnin"y d Steel Research. Assos.N

ciation, London, England, av British. comparir. Application c'to`lier'28, 194,9,` Serial No. 1,2'4,`184 Iny Greajt'Bi-itain October28`g1948 v This invention relates to Sawbreaker-'block to besused ,for the purpose. of limiting to a safe iig-` ure the.. load which can .bel appliedzto parts oi machines. In particular, the breaker-blockof-the invention. may. beused in a. rolling mill.` for the purpose of. vlimiting the., load. 'which'. can be ap-` pliedto the 4roll neck, butaitimaylalsof-be'employec. for an: analogous. purpose inzother.I ma,` chimes; for: example, in'power. operatedshears.

In'mostfrol'ling. mills Vtheiforrn of breaker block atzpresent' usedy consists ofraround or` .square cast iron block which. is placed on top ofi` the chock andreceives the. endxofthe screw-downgear. screwin the. middleoff'its upperface."y The-undersidexof 'the blocklis. recessed, .so that it .bears on' therl chock.` at-.itscperipheryz or atfits ends only;l When atsuicient; overload occurs,'.the Yblock "frac'-r turesiandz allowsithe chock: to frise.- Theloadat which'. this: will happen is, howeyen: uncertain owing; toy the inconsistencyy of the-iz mechanical. properties. of the .material ofv which; the .breaker blockais: composed; .The .presenti invention provides;.a,breakernblock so Vdesigned that the breaking load can be predetermined within close limits.

According to the present'invention a breaker block comprises a bodyvmember havingla-chamber therein and a load receivingmemberbearing against the outer faceof a diaphragm secured over' tliechambe'rand means for maintaining -uidzunder pressure in said chamber wherel` by? a .loadlapplied between thel load receiving memberl andthe rolling milllc'hock is limitedvlto the. s1.nnof" the fluid load onatheI inner faceof the diaphragm.y and the load.` required to shear the diaphragm.

Ther-accompanying drawings illustrate, byfway eifexample', a. breakenblockfor a rolling mill. In these drawings:

Figure 1 is a sectional side elevation of a rolling mill showing the breaker block in its Working position, and

Figure 2 'is a perspective diametrical section through the breaker block. v

In the particular construction shown in the drawings the base of the breaker block is formed by a circular body I, 7 inches in diameter and 1% inches thick adapted'to rest upon the chockv II of a rolling mill. The upper face of the body is recessed to form a circular chamber 2. The upper part of this chamber 2 `is surrounded by a short upstanding spigot 3 having at its upper end a sharp inwardly projecting lip 3a which forms the actual mouth of the chamber. This spigot is hardened and ground. A diaphragm 4, ofsoft copper, 0.005 inch thick, is laid over the 'e 'claima- (01. sos-57),. f

mouth of fthe chamber and clamped `between the upper. face of.A the body. .and theundersideiof: a second 'body member inthe form; of. anfannular steel disc 5, which. secondcbody. memberz'mates with the body Ifandi's secured toitby holtsz.

A: soft copper .ring 1 surrounding the fspigot; .3., provides a seal to ensure that.` the .chamber 2:.iS, fluid tightt .'I'hebo'rezof the aimul'ar; discnis. tapered upwardlyfiromla diameteriofl/zl, inches at thebottom-to` a top.4 This bore is '.iilledl bya truste-conical steel disc 8, one inch .thick,s.whose :lower surface =is;ac; curately flush with thatof the annularzdiscui Thelower'faceof theconicall disc Sis hardened and ground, .the periphery of.v thisiace: beinggre-A lieved to form' a sharp lipra,whichlis;ayclosettl with the ylip 3a on the spigonsc' :that theseftwo` hardened *and ground. lipsformlin effect. a punch anddie. 'The chamber 2 face-of the lbody I -through..aninletzpassage communicates with. they lower provided:with a. nonereturn,valvei IDL.. Through this passage' uidlis. injected :.intoi.. the chamber 2'so asto compresmthe;airalready in thevc'hamber. to VVpress'urer..whichzzwill supporti the, diier-g ence betweenethe .load ati-which the. breakenis intended topperatefandfthei loadrequiredrto. shear the diaphragm: 14.1 Thedevice is i .installedginthe mill. with the underside. cir-the;l boidy.v resting-.Qn the top vofgthe chock-.I l and the end or the screw l 2y of...the. screw-down ='geari bearingon the;upp.er snriacegof .asphericall'ys seated: pad I 3i ITheun-- derside of; the.' Trustee-conical disc; 3VN rests'v upon the diaphragmill; su` thatzthe. load .which canaxbie applied. to. the chock?.` vI I #isi limited to.1theeuid load on the, underside, o'zltheldiaphragrm plusrsthe load required to shear'theffdiaphragm'. ,Annex-- cess of this fluid thrust over the roll force is carried bythe annular disc 5. It will be seen that f if the thrust from the screw I2 should exceed the fluid thrust by more than the shearing force of the diaphragm 4, shearing will take place. This will enable the'fluid to pass into the clearance space I4 between the frusto-conical disc 8 and the annular ring 5 and also into the space which will have opened between the conical surfaces of the disc 8 and of the ring Sas the former descends Arelative to the latter. The chock Il will now be free to rise and relieve the force on the mill. The diaphragm 4 is not intended yto contribute to the load carrying capacity but only to prevent the escape of Iiuid until operatlon'of,

the breaker takes place.

In two tests with this apparatus iitted to an Vdiameteriof 21/2 ,inchesat the ber 2 was -lled with nitrogen gas from a containing cylinder. The breaker block operated at total loads of 6.4 and 6.3 tons. The pressure of the nitrogen in the chamber was the same in both cases. A third test was carried out to determine the load required to shear the diaphragm with thechamber lled with air at ambient temperatureand pressure. The load in this test was 0.95 ton.

If a liquid is employed any convenient means and procedure may be employed for the injection of the liquid into the chamber 2 to produce the required pressure. One method of effecting this operation is to place the assembled breaker upside down in a compression testing machine. An open-topped cylinder is screwed into the inlet passage 9 in the body l and filled with the liquid. A piston is inserted in the cylinder and forced down with the straining motion of the testing machine until the load indicated reaches a figure calculated from the area ofthe piston and the pressure required. The piston and cylinder are then `removed and theinlet passage closed by a plug' IOLto prevent the entry of dirt. Preferably ai plain pistonis used, fitting the cylinder sufliciently closely to make packing unnecessary. However, the piston may be provided with a loose head having astem tting'into4 a bore in the body of the piston, thus allowing a soft rubber packing4 to be interposed Abetween the body and headand` compressed by the differential pressure due tothe unsupported area of the cross? 'section .of the stem.

Having n'ow particularly described and ascertainedfthe nature of my said invention and in what'manner the sameis to be performed, I de- 'clarethat what I claim' is: .y l

1. A breaker vblock comprising a body member having a chamber therein, a diaphragm extending over fthe chamber,.means including an annular member secured-tosaid body member to clampfs'aid diaphragm to said body member to provide a, hermetic vseal for said chamber, a load receiving memberxwitiiin.V the ybore of said annular member and seated upon said diaphragm, thediaphragm having a shear resistance equal only to` ai minor fraction of the load to be carried by 'said load rreceiving member, said body member being provided with'lanopening for the introduction-of. a pressure fluid into said chamber, and meansfor closinglsaid' opening to prevent the escapel of the pressure fluid vfrom said chamber, whereby the load whicncan. be applied between therload. receiving member and the body memberis limited tothe sum ofthe iluidload on the innerv face of vthe-diaphragm and the load required to shear thediaphragm.

2. A breaker block according to claim 1, wherein the peripheral edge of the load receiving member and the adjacent edge of said body member at the opposite side of said diaphragm are formed with co-operating lips for shearing the diaphragm when the load receiving member moves inwards. l

3. A breaker block as recited in claim 1, wherein said load bearing member has a spherical surface at the face thereof opposite said diaphragm, in combination with a pad member having a. complementary spherical surface in engagement with the spherical surface of the load bearing member.

4. A breaker block according to claim 1, wherein said annular member and said load receiving member have cooperating stop surfaces preventing movement of said load bearing member with respect to said annular member by pressure exerted upon said diaphragm yby a pressure iluid within said chamber.

5. A breaker block as recited in claim 4, wherein the annular member has a bore including an inwardly arin'g'conical wall surface, and said load bearing member has a complementary comcalwall surface seated against the conical wall section of the annular member; said complementary wall surfaces constituting said stop surfaces.

6. A breaker block as recited in claim 5, wherein the bore of said annular member has a cylindrical wall section between said conical wall sur@ face and the face thereof engaging said diaphragm, said load bearing member has a cylindrical wall section opposed to and of less diam' eter than the cylindrical wall section of said annular member, and said load bearing member has a cutting lip projecting outwardly from the cylindricalwall surface thereof, whereby shearing of said diaphragm opens communicationv between said chamber and the interspace lbetween the respective cylindrical wall sections of said annular member and said load bearingmember.

WILLIAM HEAP BAILEY. I

. REFERENCES CITED The Afollowing references are of record in the file of this patent: f

UNITED STATES PATENTS France A-- Jan, 16," -1931 

